The problem you experience with GDDR6 and channels is width. You get higher in size but you'll never be able to fill the memory fast enough to be cost effective. Also why HBM exists. Lets say the top is 960GB/s for an A6000 for GPU memory. HBM3 is 3.35 TB/s.
If Intel wanted to make better GPUs it needs to switch to HBM.
You say nope and then proceed to say exactly what I said. When if the ICs are limited to 16Gbit density for now, the 24GB limit you mentioned was wrong, since you assumed single rank was the highest possible.
As for HBM, that is earmarked for their gaudi 3 line. There is no chance of it being put into a consumer product, as it would be like selling gold at pyrite pricing.